Air control dampers commonly involve construction based on a generally rectangular frame, and a plurality of parallel blades extending from side to side across the frame. The blades are hinged or pivotally mounted in the frame, so that they may be swung between closed and open positions. It is thus possible to regulate and to restrict and control air flow at the outlet or inlet.
It is normal to provide a movement linkage inter-connecting all of the blades so that they all may be moved in unison. Some form of tool, or key, is usually used to operate the linkage, and the linkage is usually provided with a tool receiving recess or other like receiver, by means of which the key may readily be inter-engaged with the linkage.
The dimensions of such air dampers vary dependent upon the size of the air duct or air opening which they are intended to control. Certain standard sizes may be held in stock. However, in some cases it may not be possible to stock standard air dampers in a sufficient range of sizes. Sizes may not be known until an order is received. Various quantities of dampers in different sizes are specified, and then production is commenced.
The steps involved in production usually entail cutting lengths of material to form the frame, cutting blades to the appropriate length, fitting the blades within the frame, interengaging the linkage mechanism, and blade pivots, and fastening the frame portions together at their corners.
The design and construction of the blades has involved either a solid extrusion of aluminum or roll-formed steel or aluminum. In order to reduce expense of the material, it has been proposed to use a thin sheet material which may be formed into a blade section. Various different blade section formations may be roll formed in this way.
The blade pivots may be formed by cutting notches at the ends of the blades. Alternatively, pivot members are attached to the blade ends. These pivots are usually then received in holes in the sides of the frame. The formation of the blades therefore involves several different manufacturing steps, and the assembly of the blades and the frame also involves a number of assembly steps, and the use of a number of different components.
Much of this work must be done by hand labour. Consequently, the fabricating of such air dampers is a relatively inefficient and expensive operation. As a result this significantly increases the cost of the dampers.
Clearly, it is desirable to provide an improved damper construction, wherein much of the hand fabrication techniques are eliminated, and which are particularly suitable to the fabrication of dampers in a wide variety of different sizes, using standardized materials, and a minimum of hand labour.